This is a note to let you know that I've just added the patch titled
clockevent: sun4i: Fix race condition in the probe code
to the 3.17-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
clockevent-sun4i-fix-race-condition-in-the-probe-code.patch
and it can be found in the queue-3.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6bab4a8a1888729f17f4923cc5867e4674f66333 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
Date: Tue, 18 Nov 2014 23:59:33 +0100
Subject: clockevent: sun4i: Fix race condition in the probe code
From: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
commit 6bab4a8a1888729f17f4923cc5867e4674f66333 upstream.
The interrupts were activated and the handler registered before the clockevent
was registered in the probe function.
The interrupt handler, however, was making the assumption that the clockevent
device was registered.
That could cause a null pointer dereference if the timer interrupt was firing
during this narrow window.
Fix that by moving the clockevent registration before the interrupt is enabled.
Reported-by: Roman Byshko <rbyshko@xxxxxxxxx>
Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/clocksource/sun4i_timer.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
--- a/drivers/clocksource/sun4i_timer.c
+++ b/drivers/clocksource/sun4i_timer.c
@@ -182,6 +182,12 @@ static void __init sun4i_timer_init(stru
/* Make sure timer is stopped before playing with interrupts */
sun4i_clkevt_time_stop(0);
+ sun4i_clockevent.cpumask = cpu_possible_mask;
+ sun4i_clockevent.irq = irq;
+
+ clockevents_config_and_register(&sun4i_clockevent, rate,
+ TIMER_SYNC_TICKS, 0xffffffff);
+
ret = setup_irq(irq, &sun4i_timer_irq);
if (ret)
pr_warn("failed to setup irq %d\n", irq);
@@ -189,12 +195,6 @@ static void __init sun4i_timer_init(stru
/* Enable timer0 interrupt */
val = readl(timer_base + TIMER_IRQ_EN_REG);
writel(val | TIMER_IRQ_EN(0), timer_base + TIMER_IRQ_EN_REG);
-
- sun4i_clockevent.cpumask = cpu_possible_mask;
- sun4i_clockevent.irq = irq;
-
- clockevents_config_and_register(&sun4i_clockevent, rate,
- TIMER_SYNC_TICKS, 0xffffffff);
}
CLOCKSOURCE_OF_DECLARE(sun4i, "allwinner,sun4i-a10-timer",
sun4i_timer_init);
Patches currently in stable-queue which might be from maxime.ripard@xxxxxxxxxxxxxxxxxx are
queue-3.17/clockevent-sun4i-fix-race-condition-in-the-probe-code.patch
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